我已经有一段时间没用过Entity Framework了,现在我要使用EF 5,但是不会这个查询语句:
SELECT
c.OrganizationName as CompanyName,
c.OrganizationKey as CompanyId,
ISNULL(a.Line1, '') as Line1,
ISNULL(a.Line2, '') as Line2,
a._CityStateZip as CityStateZip
FROM Organizations c
JOIN Addresses a ON c.AddressKey = a.AddressKey
WHERE c.OrganizationName LIKE @term + '%'
AND c.IsSuspended = 0
AND c.IsActive = 1
与...相同:
var results = (from c in adms.Organizations
where c.OrganizationName.StartsWith(term)
where !c.IsSuspended
where c.IsActive
select new
{
CompanyName = c.OrganizationName,
CompanyId = c.OrganizationKey,
Line1 = (string.IsNullOrEmpty(c.Address.Line1) ? string.Empty : c.Address.Line1),
Line2 = (string.IsNullOrEmpty(c.Address.Line2) ? string.Empty : c.Address.Line2),
CityStateZip = c.Address._CityStateZip
}).ToList();
当我运行LINQ to SQL代码时,出现以下错误:
Could not translate expression
'Table(Organization).Where(c => c.OrganizationName
.StartsWith(Invoke(value(System.Func`1[System.String]))))
.Where(c => Not(c.IsSuspended))
.Where(c => c.IsActive)
.Select(c => new <>f__AnonymousType2`5(
CompanyName = c.OrganizationName,
CompanyId = c.OrganizationKey,
Line1 = IIF(IsNullOrEmpty(c.Address.Line1),
Invoke(value(System.Func`1[System.String])), c.Address.Line1),
Line2 = IIF(IsNullOrEmpty(c.Address.Line2),
Invoke(value(System.Func`1[System.String])), c.Address.Line2),
CityStateZip = c.Address._CityStateZip))'
into SQL and could not treat it as a local expression.
我是否完全忽略了什么?我认为我可以在LINQ to SQL中使用string.IsNullOrEmpty。